Process for producing alpha foamy body adapted to be used in making cellular concrete



Patented May 3, 1932 JOHN A. RICE, OF BERKELEY, CALIFORNIA, ASSIGNOR TOTHE BUBBLESTONE COM- P.AJ\TY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATIONOF PENNSYLV PROCESS FOR PRODUCING A FOAMY BODY ADAPTED TO BE USED IN a2, :o r.

CELLULAR CONCRETE K0 Drawing. Application filed April 24,

The present invention relates to improvements in the process of makingcellular concrete, such as has been described in my copendingapplication, Serial No. 608,349. In the latter application a method wasset forth for introducing gas bubbles, preferably produced by whipping agelatinous substance in the presence of water, into a foam or lather.This foam, as described in said application, is mixed into the cement ina dry or a soft state and produces a cellular concrete which althoughpossessing'many of the working ualities of ordinary concrete isextremely hght in weight and may even form a substitute in many casesfor wood.

The present invention relates more particularly to the process formaking the foam or lather, it having been found by successiveexperiments that by the introduction of various agents the quality ofthe foam may be improved so that the walls of the bubbles arestrengthened and the foam is rendered less apt to dissolve or to breakup while it is being mixed into the cement.

While in the co-pending specification a gelatinous mixture wasconsidered as a suitable base for producing the foam, I have establishedby later experiments that any protein substance in colloidal solutionwill serve to make foam or lather for cellular concrete. The followingforms of protein are especially suitable: Egg albumen; blood albumen;and casein. I

I further discovered that foaming agent may be added to the solutionwith beneficial results. As the first one among these foaming agents Iwill mention rosin. The latter is dissolved in acetone or alcohol andthen sufficient formalin added to cause the rosin to disperse in theform of a very fine precipitate when added to an aqueous liquid. Thissolution is poured into the gelatinous or other colloidal proteinsolution. The precipitate of rosin remains in suspension and when thesolution is beaten to a froth becomes a part of the walls of the bubbleswhich constitute the froth. The presence of rosin, forming a constituentof the material of the walls of the bubbles, acts as a protector andstrengthener after the bubbles have been formed and 1923. Serial No.634,370.

acts as a foaming agent before the bubbles have been formed, insofar asit lowers the surface tension of the liquid and adds to its viscosity.

While rosin was originally used for this purpose, further experimentsshowed that other resins, namely, copal, Bakelite varnish, and also suchmaterials as celluloid and rubber may be used instead of rosin. For thefoaming agent the following formulas may be used:

Rosin, 20 grams; acetone, cubic centimeters; formalin, 34 'cubiccentimeters; or if alcohol is used as a dissolving agent: rosin, 100grams; alcohol, 335 cubic centimeters; formalin, 181 cubic centimeters.

In making up either of these solutions or other similar solutions ofceluloid or rubber, the proportions of acetone and formalin or ofalcohol or other solvent and formalin must be carefully balanced, bothto each other and to the amount of resinous substance used. The compoundshould be mixed in the following manner: The resinous substance shouldbe dissolved in the solvent and the formalin should be added. in smallportions, portion by portion, shaking the container in the meantime,until the solution becomes slightly cloudy. Then the solution may betested by dropping a drop or two into a vessel of clear water. If thesolution emulsifies at once and spreads all through the water, formingamilky dispersed precipitate or colloidal solution, the proportion ofthe resinous substance to the solvent and to the formalin is correct.But if the precipitate is not fine enough to remain in suspension, moreformalin or more solvent should be added drop by drop, repeating thetest given above at intervals. It will be found that a condition ofmaximum difi'usibility will be attained so that the precipitate diffusesthroughout the water without clotting.

In using the above described foaming agent the following proportions mabe used in making a lather suitable for making cellular cement:

Gelatin or glue, 0.15 percent more or less;

foaming agent, 0.10 percent; water, 99.75 perum cent.

satisfactory results with other foamingagents, among which may bementioned'the following:

G1 cerol added to the foam solution is bene cial to the latter. Thefollowing formulas may be used:

Water 98.5 percent Gelatin 1.0 percent Glycerol 0.5 percent or:

Water 98.3 percent Gelatin -1.0 percent Formalin 0.2 percent Glycerol0.5 percent Further successful experiments were made oy the use ofSpanish bark, usually known as soap bark, which is a well-knownglucoside The glucoside was steeped into 99 parts of water to one partof soap bark for twenty minutes. The resulting liquor was easily beateninto a stiff froth which mixed very successfully with cement or plaster.Other glucosides and saponins were tried later w th success, namely:yucca, of several varletles, the mole plant,a local soap root which inappearance resembles an onion,--and the roots of the senega plant.Solutions from these various glucosides were used alone and also mixedwith a gelatinous solution, causing the same to foam more efficiently.

As a further foaming agent phenol may be mentioned, which when added toa solution of gelatin tends to stiffen the froth and also seems toprevent the bubbles from breaking when mixed with strong alkalinecements. Phenol also is a good preservative for the gelatin solution. Iused various phenol derivatives, among them Lysol, with excellentresults.

I noted that the effect of phenol or a phenol derivative upon thesubsequent setting of beneficial, counteracting the tendency of the gluesolution to delay the setting of the cement. The following formula mightbe used 6 this connection:

Portland cement is quite marked and very I further discovered that thevapor of chloroform ives the foama marked stability such that it ecomesmore insoluble in water or in the cement mixture. The chloroform issprayed into the chamber of the beater before the solution is beateninto a froth, that is to say, the lather is made in an atmosphere ofchloroform vapor.

I found that a foam made in this manner could be washed with waterreviously to using the same in making cel ular cement, whereby anyexcess of soluble gelatin is removed. The action of the chloroform vaporseems to harden the walls of the bubbles by toughening the films so thatthey do not easily break or go into solution in alkaline cements.

It should be mentioned that different methods may be used for mixing gasinto a solution for the purpose of producing foam or lather. Air may,for instance, be introduced under pressure, in the bottom of a tankholding the solution, and strained through a suitable filter.

I claim: 1. The process of producing a lather for making a permanentfoam which comprises dispersing -a resinous substance in alcohol, addingthe resultant dispersion to a foam stabilizing solution and mixing thesolution with an inert gas to produce a lather.

2. The process of producing a lather for making a permanent foam whichcomprises adding a dispersing agentto a resinous substance, adding theresultant dispersion to a solution whereby the resinous substance isprecipitated, and mixing the solution with an inert gas to produce alather. v

3. The process of producing a lather for making a permanent foam whichcomprises thedispersing of a resinous substance 1n the presence offormalin, adding the resultant dispersion to a solution whereby theresinous substance is precipitated and the mixing of the solution withan inert gas to produce a lather.

4:. The process of producing a lather for forming a permanent foam whichcomprises dispersing a resinous substance in alcohol in the presence offormalin, adding the resultant dispersion to' a solution, and mixing thesolution with an inert gas to produce a lather.

5. The process of producing a lather for forming a permanent foam whichcomprises adding a foaming agent to a solution, and mixing the solutionwith an inert gas in the presence of chloroform vapor to produce alather.

6. A composition of matter comprising a resinous substance, a solventtherefor and formalin in the form of a foam. a

7. A composition of matter comprising rosin in suspension and formalinin the form of a foam.

8. The process of producing a lather for forming a permanent foam whichcomprises the steps of dispersing a resinous substance, adding theresultant dispersion to a solution, whereby some of the said resinoussubstance is precipitated in the foam producing solution, and treatingthe resultant mixture with a gas to produce a' lather whereby theresinous substance is dispersed throughout the cellular walls of thelather and serves to reinforce said walls.

' JOHN A. RICE.

